#include<bits/stdc++.h>
using namespace std;

int main() {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	double y = 233333, x = 343720;
	double ret = 0;
	for (int i = 1; i < 100; i++) {
		double yy = y * i, xx = x * i;
		double dy = y;
		if (dx % x == 0)break;
		double dx = dy / 17 * 15;
		ret += (sqrt(dy * dy + dx * dx));
	}
	cout << ret;
	return 0;
}